• 분석과학
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• 제5권3호
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• pp.269-276
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• 1992

An ion-exchange/conductometric method is applied for the determination of total acidity in simulated atmospheric samples. Non-$H^+$ cations and strong acid anions are enriched by the preconcentrator columns in series and eluted through the corresponding parallel suppressor units. The conductivities from each channel correspond to the concentrations of the resulting ionized species in equivalents per unit volume. The difference is the measure of acidity due to strong acids. With 5-min sampling at a flow rate of 0.3 mL/min, the detection limits for ${NH_4}^+$ and ${SO_4}^{2-}$ are 0.3 and $0.1{\mu}equiv/L$, respectively. The acidity for samples composed of various ions can be determined without significant error, usually less than 5%. The proposed method discriminates against the artifact from the $CO_2$ dissolution. Principles of acidity measurements are also presented.

• Journal of Korean Society for Atmospheric Environment
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• 제18권E4호
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• pp.181-190
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• 2002

A novel portable device for the direct measurement of alveolar breath carbon monoxide (CO) was developed. The major components of the device include a mouthpiece, non-rebreathing two-way valve, Teflon tube, and CO dosimeter. An alveolar CO measurement can be completed within 1.5 min when using the proposed device and measurement protocol. Measurements could be read to the nearest 0.1 ppm. Humidity did not influence the CO measurements taken by the CO dosimeter, plus there were no problems associated with the recovery and carryover of CO through the device. The criterion for significance in statistical analyses was p< 0.05. The average recovery was 103 and 99% for recovery and carryover experiments, respectively. Test results using the proposed alveolar CO measurement system reflected a good reproducibility. This reproducibility was also supported by the finding that the relative standard deviations (RSDs) of the data sets were less than 7％ for the loss experiment and less than 8% for the carryover experiment. Consequently, it would appear that the proposed device can be effectively applied to measure CO levels found in breath, thereby overcoming several disadvantages associated with the conventional bag and adsorbent tube sampling methods.

• 한국대기환경학회지
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• 제20권6호
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• pp.759-771
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• 2004

This study analyzed concentrations of volatile organic compounds (VOCs) produced from incineration of plastic wastes at $600^{\circ}C$. The plastic wastes used in this study included polyethyleneterephthlate (PETE), high density polyethylene (HOPE), polyvinyl chloride (PVC), low density polyethylene (LOPE), polypropylene (PP), polystyrene (PS) and other. Plastic wastes were heated from room temperature upto $600^{\circ}C$ providing the compressed air inside of a small-scale electric furnace for 90 minutes and then they were oxidized (incinerated) for 60 minutes at $600^{\circ}C$ maintaining the same air supply. VOCs emitted from the incineration process were sampled using an air sampling pump and Tedlar air bags for 150 minutes and then the components and concentrations of the VOCs were analyzed by a GC-MS. The most prominent chemical structure of the VOCs obtained from the incineration process of the HOPE, LOPE and PP, which include ethylene groups in their main chains, was identified as aliphatic hydrocarbons such as 1-hexene. However, aromatics such as benzene were major chemical structure from the incineration of PETE, PVC and PS which include benzene rings in their main chains. This study estimated the total VOC production from the incineration of the plastic wastes based on the real plastic waste production and the emission factors. 64% and 27% of the total VOC emissions consisted of aliphatic hydrocarbons and aromatics, respectively, which have double bonds within their molecular structure and thus a high ground level ozone formation potential.

• 한국대기환경학회지
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• 제23권6호
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• pp.666-674
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• 2007

In this study, sampling and analysis was carried out for 13 compounds, in order to investigate the odorous compound emissions from landfill stacks and surrounding ambient air. These results revealed that concentration of hydrogen sulfide was $0.13{\sim}0.66\;ppb$ in the ambient air. Also, concentrations of hydrogen sulfide ($151{\sim}358\;ppm$) were the highest value in odorous sulfur compounds from landfill stacks. In case of VOC, toluene was obtained the highest out of volatile organic compounds. It was found that the concentrations of hydrogen sulfide near the landfill was higher than that inside city such as Seoul although it was located in a rural area. The result was due to the effect of hydrogen sulfide emitted from landfill stacks.

• 한국대기환경학회지
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• 제9권4호
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• pp.303-309
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• 1993

An observational study of urban heat island was carried out using field data obatined during 6 days in May and August 1992 in Chunchon(population size 180.000). Air temperature was measured at 64 points along two sampling ruoutes by themisters attached to cars. Both routes cover urban and rural area and across the cneter of urban area. Continuous observation of air sonde was perfomed to clarify heights of nocturnal boundary layer(NBL) at the center of urban area. Surface meteorological observations were performed at both urban and rural sites. This study showed that heat island phenomena was obviously observed at the urbanized area during the night time with low wind speed. The average NBL heights exteded to about 10 meters, but varied with meteorological conditions. After sunset, the air temperature decreased with time at both sites and cooling rate at the urban site was greater than the rural site. The maximum heat island intensity was 7.5$^{\circ}$C at 21 LST, May 4. Usingthe two meteorological data sets obtained from urban and rural sites, the air pollutant concentration was calculated by Gaussian plume model which can obtain not only horizontal distribution of concentration but also vertical distribution. The result indicated that the concentration resulted from urban meteorological data set was lower than that from rural meteorological data set. It was also calculated that the air pollutant extended to higher level in urban meteorological data set than that in rural meteorological data set.

• 한국대기환경학회지
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• 제15권5호
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• pp.657-665
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• 1999

Particulate matter produced by diesel engines is of concern to cngine manufactures because of its environmental impact. The majority of diesel particles are in the range of smaller than 1 ${\mu}{\textrm}{m}$. Because of their tiny volume, ultrafine diesel particles contribute very little to the total mass concentration which is currently regulated for automobile emissions. Ultrafinc particles are known to have deleterious effects upon human health cspecially because they penetrate deeply human respiratory tract and have negative effects on the health. In this study, the engine exhaust gas was diluted in a dilution tunnel and the particle size distribution was measured using the scanning mobility particel sizer system. Measurements of the number and the mass concentrations of the diesel exhaust were made under different engine ooperating conditions. The dilution sampling system provided a common basis for collection of the exhaust by cooling and diluting the source emission prior to the measurement. The measurement results showed that the particle size distributions of the exhaust from the diesel vehicles equipment with either heavy-duty or lignt-duty diesel engines, were similar in the particle size range of 0.08~0.2${\mu}{\textrm}{m}$.

• 한국대기환경학회지
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• 제14권2호
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• pp.95-106
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• 1998

Volatile organic compounds (VOCs) from Ca to C9 were investigated with nine ambient air samples collected in April 26, August 17, 1996 and January 23, 1997 in a Seoul site. On each sampling day, three 2-hr integrated canister samples were collected in early morning, early afternoon and late afternoon, respectively to study temporal . variation of VOCs. Most of VOC species showed diurnal variation with higher concentrations in the early morning and lower concentrations in the afternoon. The concentrations of light alkanes were high, probably due to the emission from liquefied petroleum gas (LPG) and evaporation of gasoline. Especially, the concentration of propane was the highest in the morning samples. The concentrations of propane, ethylene, acetylene, and toluene were prominent in their hydrocarbon groups, respectively. These components were the main source of car exhaust, gasoline evaporization, LPG, or solvent usage.

• Journal of Radiation Protection and Research
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• 제31권1호
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• pp.9-15
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• 2006

대기 중으로 방출된 방사성 물질의 이동 확산 현상을 이해하기 위하여 장거리 대기 확산 모델 LADAS가 개발되었다 개발된 수치모델의 검증을 위하여 ETEX 장거리 확산실험 결과와 비교하였다. 비교결과 LADAS모델 내 혼합층 높이를 일정하게 준 경우보다 Richardson number를 이용하여 혼합층 높이를 계산한 결과가 관측 값에 가장 근접함을 알 수 있었다. 또한 일부 포집 지점에서 관측된 농도의 시계열 자료와 비교한 바 계산 값은 어느 정도 일치하고 있었다.

• 한국대기환경학회지
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• 제24권1호
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• pp.100-107
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• 2008

The objective of this study was to quantitatively estimate PM-10 source contribution in Gumi City, Korea. Ambient PM-10 samples were collected by a high volume air sampler, which operated for 84 different days with a 24-h sampling basis, from June 14,2001 though May 19, 2003. The filter samples were analyzed for determining 13 inorganic elements, 3 anions, and a total carbon. The study has intensively applied a receptor model, the PMF (Positive Matrix Factorization) model. The results from PMF modeling indicated that a total of seven sources were independently identified and each source was contributed to the ambient Gumi City from secondary sulfate (34%), motor vehicle (26%), soil relation (5%), field burning (3%), industrial relation (3%), secondary nitrate (22%), and incinration (7%) in terms of PM-10 mass, respectively.

• 한국지반환경공학회 논문집
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• 제23권10호
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• pp.21-31
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• 2022

최근 세계우주국에서는 달에 얼음이 매장되어 있음을 발견하고 경쟁적으로 달 얼음 탐사 미션을 추진 중에 있다. 달에서 얼음을 탐사하고 지하 샘플을 채취하여 지층의 구성을 측정하기 위한 연구는 필수적이다. 착륙선 및 탐사로버는 달의 극지방에 위치한 얼음과 자원을 분석하기 위하여 시추 장비가 필요하다. 이러한 장치는 달 환경의 극한 조건에서 작동할 수 있는 신뢰성을 가져야 하며 소형, 경량, 저전력, 고효율의 장치여야 한다. 국내에서도 달 지하 1m 까지 매장되어 있는 얼음 샘플채취 및 지층구조 분석이 가능한 무인 시추장비 개발을 진행하고 있다. 본 논문은 지금까지 개발된 시추장비와 시추정보를 이용한 지반강도를 평가하는 기법에 대해 소개하고자 한다.